Automatic lifting mechanism



Sept. 20, 1938. A 2,130,354

AUTOMATIC LIFTING MECHANISM Filed May 16, 1938 3 Sheets-Sheet l [12 ven for Neil B. Mad-sen P 0, 1938. N. B. MADSEN AUTOMATIC LIFTING MECHANISM Filed May 16, 1938 3 Sheets-Sheet 5 w x III III! 0 0 a -3 2 o 6 o Mm o B a g M a u, a w F 3 6 f a r R. I w w w a I 4 m P. m

Invenzor Neil B. Madsen Attorney Patented Sept. 20, 1938 EN TED STATES FATENT OFFICE 14 Claims.

(Granted under the act of March 3, 1883, as amended April 30, 1928, 370 O. G. 757) The invention described herein may be manufactured and used by or for the Governmentfor governmental purposes without the payment to me of any royalty thereon.

This invention relates to an automatic lifting mechanism for use, with hoists, cranes or other lifting devices, in connection with a load or loads requiring repeated and systematic engagement and disengagement.

The device as hereinafter described relates spe cifically to engaging, disengaging, and lifting means for use with cranes, or the like, whereby a load comprising a spillway gate, emergency gate, or similar structure may be readily engaged for elevation and transportation to a predetermined location, and when so placed in desired position and elevation may be readily disengaged, the various steps in the cycle of engagement and disengagement being automatically performed by the manipulation of the elevation of the engaging and lifting means with reference to the load.

This device may be used in single units or in any desired multiples thereof as hereinafter disclosed.

The primary object of this invention is to provide means whereby the lifting member of a gantry crane or the like may be automatically engaged with a designated gate for the purpose of effecting a desired change in gate elevation or position, and then be disengaged from the gate, by the manipulation of the lifting member relative thereto.

A further object of this invention is to provide, in a spillway gate assembly comprising a plurality of superimposed segments, means whereby the individual segments may readily be connected to their fellows, or disconnected therefrom preparatory to being moved.

Other objects of the invention will become apparent in the following description which, with the accompanying drawings, discloses a preferred embodiment of my device.

In the drawings:

Figure l is a fragmentary elevation, partly in section, through a bay of a spillway dam, and shows a spillway gate assembly together with a multiple assembly of our automatic lifting mechanism, in operative position therein.

Fig. 2 is an enlarged fragmentary sectional elevation of the lifting and engaging mechanism shown in Fig. 1. This view is taken on line 2--2 of Fig. 3 and in the direction indicated.

Fig. 3 is a sectional end elevation of the mechanism shown in Fig. 2, taken on line 33 and in the direction indicated.

Fig. 4 is a fragmentary View, partly in section, of a unit of automatic lifting mechanism showing the arrangement and position ofthe parts when 5 detached from a load.

Fig. 5 is a view of the mechanism shown in Fig. 4, showing the arrangement and position of the parts when about to engage a load.

Fig. 6 is a View of the mechanism shown in 10 Fig. 4, showing the arrangement and position of the parts when a load has been engaged.

Fig. 7 is a view of the mechanism shown in Fig. 4, showing the arrangement and position of the parts when set to disengage a load.

Similar reference characters refer to similar parts throughout the several views.

In Fig. 1, dam I is equipped with a crest 2 above which spaced piers 3 and 3a arise, providing a spillway 4 through which a flow of water may discharge over the crest 2. A suitable spillway gate, as one comprising a lower segment 5 upon which is superimposed an upper segment 6, is provided whereby the discharge area of the spill- Way 4 may be controlled. The spillway gate is suitably restrained against other than vertical movement, by any of the well known means ordinarily employed for this purpose.

It is to be noted that, in place of two gate segments as lower segment 5 and upper segment 6, a spillway gate may comprise a single segment, in which the construction would be substantially as shown for lower segment 5. However, conditions might indicate the use of a gate having more than two segments, in which case the additional segments would each be constructed substantially as shown for segment 6. In general, the number of segments required for a gate will be determined by the available clearance between the deck of the dam structure and the upper limit of travel of the means, as a gantry crane, used for placing and operating the gates. Should the height of the gate exceed the available clearance, the multiple segment constructions would be ordinarilyrequired; whereas the use of a gate comprising a single segment would normally be indicated if such a gate could be lifted clear of the dam structure by the placing and operating means provided.

For supporting the spillway gate in other than closed position, suitable means are provided, as lower latches l and 8 and upper latches 9 and IE pivotally mounted in a vertical plane in the piers 3 and 3a. These latches are adapted to engage with suitable projections from the ends of the t iqpm seal it, terminating segment 5, is brought into contact with the crest 2. The area of the spillway opening may thus be controlled over a range of from no flow to maximum flow by increments of the vertical spacing of rack bars H, I2, 13 and. M.

It is to be understood that Fig. 1 shows only a portion of a dam, the number of piers and of gates, and also the number of segments per gate, being dependent upon the design requirements of the structure.

The spillway gate is raised or lowered as required by suitable hoisting means as sheave blocks it, here shown as two in number, connected by cables ll to a gantry crane or the like, not here shown, adapted to move along a deck superstructure, likewise not shown, superimposed upon the spaced piers of the dam as 3 and 3a. Each of the sheave blocks I6 is connected by suitable means, as by lifting pin l8, to a crosshead 19, formed by spaced crosshead plates 20. The crossheads l9 are held in spaced relation by guide beam 23, provided at each of its ends with vertically disposed transverse diaphragms 22 upon which are mounted vertical guide angles 23. The spaced crossheads l9 are so disposed between the diaphragms and guide angles that they are restrained from all relative displacement therewith except in the vertical plane, in Which their displacement is limited by guide beam upper stops 24 and guide beam lower stops 25, all of which are fixed to the guide beam 2|.

Coacting links 2! and 28 are disposed between and normally depend vertically from the spaced crosshead plates 29 being pivotally mounted upon parallelly disposed link pins 29 secured thereto in a horizontal plane. Each of the links 21 and 23 is provided at its lower end with a cylindrical load bearing member 30, and at about its midsection with a link camming surface 3|. The upper end of link 2'! is provided with a link stop 32, and that of link 28 with a link arm 33. Equal and opposite synchronized angular displacement of links El and 28 is provided for by meshed gear teeth 3 radially disposed upon the links 21 and 23 about the axes of link pins 29. In order to limit to a desired minimum the mutual approach of the links, suitable coacti-ng stops as lobes may be provided.

A sear 33, suitably pivoted near its midpoint on sear pin 3? mounted in spaced crosshead plates 25, is disposed with its heavy end 38 adjacent the link stop 32 and its light end 39 toward one of the diaphragms 22. The arrangement of the sear 35 is such that upon suificient angular displacement or" the links 27 and 28 from the vertical about the axes of the link pins 29, the link stop 32 will clear the heavy end 38 of the sear, permitting it to drop and retain the links in displaced position until the light end 39 of the sear is depressed, raising the heavy end 38 and releasing the link stop and permitting the links to resume their original substantially vertical position. A suitable trigger means, as trigger screw 43 adjustably secured in bracket 4|, is mounted upon that diaphragm 22 adjacent the light end 39 of the sear 35, and is so positioned relative thereto that when the crosshead l9 approaches the guide beam upper stops 24, the trigger screw 40 will engage the light end of the sear and raise the heavy end 38 clear of engagement with the link stop 32.

It is to be observed that each of the guide beam crossheads l9, together with the associated links, link pins, sear, and lifting pin, is arranged to move in unison with the hoisting means as represented by the sheave blocks and, except as limited by the stops 24 and 25, independent of the guide beam 2|.

The gate upper segment 6 is provided with upper lifting hooks 42 each arranged in vertical alignment with the crossheads I9. Each of the hooks 42 is provided at its upper end with a sister hook arrangement comprising a pair of re-entrant arcuate surfaces 43 adapted to be engaged by the cylindrical load bearing members 30 of the links .21 and 28. The top of the hook 42 forms a. hook camming surface 44. The shank of hook 42 is loosely positioned longitudinally and transversely within the gate upper segment 6 by means of spaced longitudinal members 45, forming a part of the structure of gate section 6, and spaced transverse members 46 aflixed members 45. The hook 42 is, for normal operation, positioned vertically by means of a wedge 41 disposed upon bearing plate 48, which in turn is mounted upon the top surface of the longitudinal members 45. Pierced cars 49 are afiixed to members and extend upwardly therefrom, and in alignment with an aperture 50 piercing the shank of hook 42, adapted to receive the wedge 47. The aperture 50 is sopositioned that when wedge 41 is in place the hook camming surface 44 and re-entrant arcuate surfaces 43 are properly positioned for engagement by the cylindrical load bearing members 30 of the links 21 and 28, as hereinafter described. To facilitate the manipulation of the wedge 41, a jack screw 5|, suitably disposed in the wedge as shown, may be provided.

The lower end of the hook 42 terminates in an eye, through which is disposed a crosshead pin It is to be noted that when the wedge 4! has been withdrawn the upper lifting hook 42 and the gate segment crosshead 53 are vertically displaceable relative to the gate upper segment 6 within limits set by gate segment upper stop 54 and gate segment lower stop 55. The excursion of crosshead 53 between stops 54 and 55 is substantially equal to that of crosshead 19 between stops 24 and 25.

In order to assure uniform displacement of the two sets of links, 27 and 28, mounted one set in each of the crossheads l9, and also of the similar links mounted in each of the crossheads 53, an interlocking mechanism may be provided con necting the respective sets of links through the link arms 33. The interlocking mechanism consists of a rectifying lever 56 pivoted at its midpoint about midway between the crossheads and connected from its ends via connecting rods 51 to floating levers 58 and thence by means of floating rods 59, reversing levers 60, and connecting links 6| to the link arms 33. A detachable handle 62, adapted to engage an end of rectifying lever 56, may be provided to permit the manual separation of pairs of links 21 and 28.

The gate lower segment 5 is provided with lower lifting hooks 63 each arranged in vertical alignment with the guide beam crossheads l9 and the gate segment crossheads 53. Each of the hooks 53 has a profile at its upper end in all respects similar to that of hooks 52. At their lower ends, hooks 63 are pivotally secured to the gate lower segment by means of lower hook pin 64, mounted in longitudinal members 65 which form a part of the structure of the segment. Stop angles 55, secured to members 55, are provided to maintain lower lifting hooks 63 in approximately vertical position.

To assure proper alignment between guide beam 2! and gate segments 5 and/or 5, and also between adjacent gage segments, suitable chamfered pilot pins 61 may be afiixed to and project upwardly from the top surfaces of the gate segments, engaging with complementary beveled sockets affixed to the bottom surfaces of the guide beam and of the gate upper segments.

The operation of the mechanism of the device is as follows: Referring to Fig. 1, the gate lower segment 5 is shown supported on lower latches l and 8. Gate upper segment 6 is disposed on the lower segment 5 and locked thereto through the engagement of lower lifting hooks 63 by links 2'5 and 28 of crossheads 53. These crossheads are keyed in this engaged position by Wedges 41, disposed through the apertures 55 in the shanks of the upper lifting hooks 52, as shown in greater detail in Figs. 2 and 3. The gate segments 5 and 5 are maintained in alignment by means of the pilot pins 6? and pilot sockets 68. It is to be noted that the pilot pins 51 are provided with tapered or chamfered noses, adapted to engage the beveled pilot sockets 58 under conditions of some misalignment upon their approach, and further adapted to correct such misalignment of the gate segments prior to final contact therebetween. As shown in Fig. 1, guide beam 2! is positioned on the gate segment 6, the guide beam crossheads l9 being engaged with the upper lifting hooks 52 by means of the links 21 and 28, and in turn being supported by the sheave blocks l5 suspended by the cables H from conventional hoisting and traveling means not shown, as a gantry crane. The relative positions of the mechanism as shown are those assumed either immediately after the spillway gate has been lowered upon the latches l and 8, or immediately before the gate has been lifted therefrom. The position of members under these conditions is shown on an enlarged scale in Figures 2 and 3, and the disposition of parts within the crossheads is shown in Figure 6.

Assuming that the spillway gate has just been lowered upon the latches l and 8, the gate is released by the lifting mechanism through the further slight lowering of the crossheads l9, by means of the sheave blocks 55, until guide beam lower stops 25 are contacted. This causes link camming surfaces 5i to engage hook camming surfaces 54, causing the links to spread, as shown in Figure '7, thus positioning the cylindrical load bearing members 35 of the links without the lines of engagement with reentrant arcuate surfaces 43 of the hooks. The spreading of the links also displaces the link stops 32 sufficiently to permit the heavy end 38 of sear 36 to drop into engagement therewith, as clearly shown in Figure '7, thus efiectively maintaining all of the links in spread position, through the medium of the gear teeth 35 and/or the interlocking mechanism comprising link arms 33, connecting links 6|, reversing levers 60, floating rods 59, floating levers 58, connecting rods 57 and rectifying lever 56. It is to be noted that, with two crossheads being operated in unison in a guide beam as shown, the interlocking mechanism assures synchronized functioning of the two sets of links.

After the crossheads have been lowered to the lower stops and the links spread and engaged in spread position by the sear, the crossheads are raised, through the reversing of the direction of motion of the sheave blocks E5, the cylindrical load bearing members 30 clearing the reentrant arcuate surfaces 43 of the hooks, until the guide beam upper stops 24 are contacted. Continued hoisting causes the guide beam to be raised, via the upper stops, until it clears and is free from the spillway gate. Just prior to the contacting of the upper stops by the crossheads, the light ends 39 of the sears 36 contact the trigger screws 45, displacing the heavy ends 38 from engagement with the link stops 32 and permitting the links to assume substantially vertical positions, their mutual approach being limited by the stop lobes 35. The relative positions of the various parts at this stage of the cycle of operation are clearly disclosed in Figure 4. It is to be noted that, while in the embodiment disclosed the force of gravity is utilized to return the links to the position shown, other suitable means might be employed, such as springs or the like.

The lifting mechanism and guide beam is now clear of the spillway gate and in condition to engage another gate or reengage the first. In so doing, the lifting mechanism is lowered over the gate in approximate alignment therewith, the details of the mechanism being disposed as shown in Figure 4. Continuing to be lowered, the pilot pins 6? engage the pilot sockets 58; bringing the guide beam and the gate first into the required degree of alignment and then into mutual contact. Continued lowering causes the crossheads to leave the upper stops, thus bringing the undersides of the cylindrical load bearing members 30 into contact with the hook camming surface M, along which they slide. This causes the links to separate, as is clearly shown in Figure 5. Continued lowering of the lifting mechanism causes the members 35 to drop clear of the camming surface 5 5, after which the links will mutually approach and bring the members 35 within the range of reentrant arcuate surfaces 53. The lifting mechanism, if then raised slightly, positions the various parts as shown in Figure 6, thus completing the cycle of disengagement and reengagement. The spillway gate may now be lifted clear of the piers 3 and 3a and moved as desired, or it may be raised to a different elevation and relatched, or it may be lowered, as required. It is to be noted that, to permit the gate to be placed at a lower level, it will first-have to be elevated sufficiently to permit the latches i, 8, 9 and iii to be swung vertically into the clear of rack bars ii, l2, l3 and M, respectively.

To separate the components of a segmental gate, as 5 and 5, the lifting mechanism is engaged with the upper segment lifting hooks as described immediately above. The wedges 57 are then removed, which operation may be facilitated by the use of the jackscrews 5!. This operation will be further facilitated by raising the hoist blocks it slightly, thus stressing the lifting hooks and utilizing the resultant strain to relieve the wedge. Upon removal of the wedges the hoist blocks are lowered, which causes crossheads l9 to be lowered, with hooks 42 and crossheads 53 moving in unison therewith, hook 42 no longer being restrained by the wedge 41. Since the hook 42 under these conditions moves in unison with the links 28 and 29 depending from the guide beam crossheads 19, no contact occurs between their camming surfaces 44 and 3|. However, with the wedges 41 removed, lower crossheads 53 and the parts associated therewith function toward lower segment lifting hooks B3 in all respects as hereinbefore described for crossheads l9 and upper segment lifting hooks 42, when the latter are restrained by the wedges. Thus the crossheads 53 contact the lower stops 55 and assume a position and arrangement of parts similar to that shown in Figure "7 for upper crossheads. The lifting mechanism is then raised, the crossheads 53 contacting the upper stops 54 and assuming a position and arrangement of parts similar to that shown in Figure 4, the upper segment 6 being disconnected from the lower segment 5 and free to be raised independently thereof. It will be evident that the crossheads l9, moving in unison with the crossheads 53, will also approach or contact upper stops 24, but as there is no rela tive movement between the camming surfaces 3| of the links depending from the crossheads l9, and the camming surfaces 44 of the upper hooks 42, the engagement between the links and upper hooks is constant, the removal of the wedges 4! having the effect of transferring the engaging and disengaging phases of operation from the upper crossheads if) to the lower crossheads 53.

After the gate upper segment 6 has been placed as desired on latches or in a repair or storage pit, but not on a gate lower segment as 5, the hoist blocks 16 are to be lowered until the apertures 50 in the hooks 42 are in alignment with the openings in pierced ears 49, when the wedges 47 are to be replaced, fixedly positioning the hook 42 and restoring to the upper crossheads I9 the engaging and disengaging phases of operation. The lifting mechanism may then be disengaged from the gate upper segment substantially as heretofore described for disengaging it from an assembled spillway gate.

To move a gate lower segment from which an upper segment has been removed, the guide beam is lowered upon it and the lifting mechanism .ma-. nipulated substantially as heretofore described for an assembled spillway gate. The gate lower segment is then placed as desired and the lifting mechanism disengaged therefrom as heretofore described for disengaging it from an assembled spillway gate.

To pick up a gate upper segment, and connect it to a gate lower segment, the lifting mechanism is engaged with the gate upper segment by the steps previously described for engaging it with an assembled spillway gate. The hoist blocks are maneuvered to remove the slack in the lifting mechanism, after which the wedges are removed, as heretofore described. The hoist blocks are then raised, the guide beam crossheads l9 and the gate segment crossheads 53 contacting the upper stops 24 and 54 respectively. This places the crossheads 53 in a position and arrangement of parts similar to that shown in Figure l.

The gate upper segment is then lowered upon the gate lower segment, the pilot pins 61 and pilot sockets 68 effecting proper alignment. As the lifting mechanism is then further lowered, the crossheads 53 assume a position and arrangement of parts similar to that shown in Figure 5. After the load bearing members 30 have completed their excursion of camming surface 44 and have become disposed within the reentrant surfaces 43, the lifting mechanism is raised sufficiently for the hooks 4.2 to .become stressed, when the wedges 41 are placed, thus securing the hooks relative to the gate structure and transferring to the crossheads IS the engaging and disengaging phases of the cycle of operation.

While the mechanism described is a preferred embodiment of my invention, it is to be understood that I do not wish to be limited to the precise form disclosed, since numerous modifications may be effected in the instrumentalities employed, but I do wish to include all mechanical equivalents and arrangements of parts that may fairly be considered to come within the scope and purview-0f my invention as defined in the appended claims.

I claim:

1. In a structure of the class described the combination, with a crane and a load, of a load engaging means suspended from the crane; a housing disposed about the load engaging means and displaceable relative thereto vertically within fixed limits, said load engaging means being adapted automatically to engage the load after the housing has contacted the load and the load engaging means has been lowered to load engaging position; and means within the housing coacting with said automatic means arranged to automatically disengage the said automatic means from the load by the act of lowering the said automatic means within the housing to a point below the load engaging position.

2. Ina structure of the class described the combination, with a crane and a gate, of a plurality of gate engaging means suspended from the crane; a common housing disposed about all of the gate engaging means and maintaining them in spaced relation and displaceable relative thereto vertically within fixed limits, said gate engaging means being adapted to engage the gate after the housing has contacted the gate and the gate engaging means has been lowered to gate engaging position; and means within the housing coacting with said automatic means arranged to automatically disengage the said automatic means from the gate by the act of lowering the said automatic means within the housing to a point below the gate engaging position.

3. In a structure of the class described the combination, with a crane and a load, of a load engaging means suspended from the crane; a housing diposed about the load engaging means and displaceable relative thereto vertically within fixed limits, said load engaging means being adapted automatically to engage the load after the housing has contacted the load and the load engagingmeans has been lowered to load engaging position; means within the housing coacting with said automatic means arranged to automatically disengage the said automatic means from the load by the act of lowering the said automatic means within the housing to a point below the load engaging position; and aligning means disposed upon the housing and upon the load and adapted to operatively align the load engaging means and the load.

4, Ina structure of the class described the combination, with a crane and a gate, of a plurality of gate engaging means suspended from the crane; acommon housing disposed about all of the gate engaging means and maintaining them in spaced relation, and displaceable relative thereto vertically within fixed limits, said gate engaging means being adapted to engage the gate after the housing has contacted the gate and the gate engaging means has been lowered to gate engaging position; means within the housing coacting with said automatic means arranged to automatically disengage the said automatic means from the gate by the act of lowering the said automatic means within the housing to a point below the gate engaging position; and aligning means disposed upon the housing and upon the gate and adapted to operatively align the gate engaging means and the gate.

5. In a structure of the class described the combination, with a crane and a gate, of a plurality of gate engaging means suspended from the crane; a common housing disposed about all of the gate engaging means and maintaining them in spaced relation, and displaceable relative thereto vertically within fixed limits, said gate engaging means being adapted to engage the gate after the housing has contacted the gate and the gate engaging means has been lowered to gate engaging position; means within the housing coacting with said automatic means arranged to automatically disengage the said automatic means from the gate by the act of lowering the said automatic means within the housing to a point below the gate engaging position; and interlocking means interconnecting the gate engaging means.

6. In a structure of the class described the combination, with a crane and a gate, of a plurality of gate engaging means suspended from the crane; a common housing disposed about all of the gate engaging means and maintaining them in spaced relation, and displaceable relative thereto vertically within fixed limits, said gate engaging means being adapted to engage the gate after the housing has contacted the gate and the gate engaging means has been lowered to gate engaging position; means within the housing coacting with said automatic means arranged to automatically disengage the said automatic means from the gate by the act of lowering the said automatic means within the housing to a point below the gate engaging position; aligning means disposed upon the housing and upon the gate and adapted to operatively align the gate engaging means and the gate; and interlocking means interconnecting the gate engaging means.

'7. In combination with .a lifting means and a load, a lifting hook affixed to the load, hook engaging means suspended from the lifting means, a housing disposed about the hook engaging means and relatively displaceable thereto in the line of its travel, stop means disposed Within the housing and adapted to limit the excursion therewithin of the hook engaging means, actuating means adapted to efiect engagement of the lifting hook and the hook engaging means during the downward excursion of the latter within the housing, disengaging means adapted to effect disengagement of the lifting hook and the hook engaging means when the latter approaches the lower limit of its excursion within the housing, locking means adapted to continue the hook engaging means in disengaged position during its upward excursion within the housing, and releasing means adapted to release the locked hook engaging means when the latter approaches the upper limit of its excursion within the housing.

8. In combination with a lifting means and a load, a lifting hook aflixed tothe load, hook engaging means suspended from the lifting means, a housing disposed about the hook engaging means and relatively displaceable thereto in the line of its travel, aligning means adapted to operatively align the lifting hook and the hook engaging means, stop means disposed within the housing and adapted to limit the excursion therewithin of the hook engaging means, actuating means adapted to effect engagement of the lifting hook and the hook engaging means during the downward excursion of the latter within the housing, disengaging means adapted to effect disengagement of the lifting hook and the hook engaging means when the latter approaches the lower limit of its excursion Within the housing, locking means adapted to continue the hook engaging means in disengaged position during its upward excursion within the housing, and releasing means adapted to release the locked hook engaging means when the latter approaches the upper limits of its excursion within the housing.

9. In combination with a lifting means and a load, a plurality of lifting hooks affixed t0 the load in spaced relation, a plurality of hook engaging means suspended from the lifting means, a common housing disposed about the hook engaging means and relatively displaceable thereto vertically and adapted to maintain the hook engaging means in registry with the lifting hooks, aligning means disposed upon the housing and upon the load and adapted to operatively align the housing and the load, a plurality of stop means disposed within the housing and adapted tolimit the excursion therewithin of the hook engaging means, actuating means adapted to effect engagement of the lifting hooks with the hook engaging means during the downward excursion of the latter within the housing, disengaging means adapted to effect disengagement of the lifting hooks and the hook engaging means when the latter approach 1,

the lower limit of their excursion within the housing, locking means adapted to continue the hook engaging means in disengaged position during their upward excursion within the housing, releasing means adapted to release the locked hook engaging means when the latter approach the upper limit of their excursion within the housing, and interlocking means interconnecting the hook engaging means and adapted to synchronize the cycle of operations of all of the hook engaging means.

10. In a structure of the class described the combination, with a crane and a gate, of a lifting hook affixed to the gate and provided with a reentrant arcuate surface near its upper end and a camming surface upon its upper face; link suspending means depended from the crane and adapted to motivation thereby; a housing disposed about the link suspending means and relatively displaceable thereto vertically; stop means disposed within the housing and adapted to limit the excursion of the link suspending means therewithin; coacting aligning means disposed on the gate and on the housing to operatively align the gate and the housing; a link pivotally suspended from the link suspending means; a load bearing member aflixed to the lower end of the link and adapted to eiTect primary angular displacement of the link by traversing the camming surface of the lifting hook during the early portion of the downlink suspending means; a link stop disposed upon the link; a sear pivotally mounted upon the link suspending means and adapted to coact with the link stop to retain the link in the position assumed upon the secondary angular displacement thereof; and a. trigger mounted upon the housing, and adapted to coact with the sear, when the hnk suspending means approaches the upper limit of its excursion within the housing, to release the link from its last named position.

11. In a structure of the class described the combination, with a crane and a gate, of a pair of spaced apart lifting hooks affixed to the gate and rovided each with a pair of oppositely disposed reentrant arcuate surfaces near the upper end and a pair of camming surfaces upon the upper face; a pair of link suspending means depended from the crane and adapted to motivation thereby; a housing disposed about the link suspending means and relatively displaceable thereto vertically and adapted to position the link suspending means in registry with the lifting hooks; stop means disposed within the housing and adapted to limit the excursion therewithin of the link suspending means; coacting aligning means disposed on the gate and on the housing to operatively align the gate and the housing; two pairs of links pivotally suspended one pair from each of the link suspending means; synchronizing means attached to both links of each pair and adapted to provide uniform angular displacement thereof; load bearing members affixed one to the lower end of each of the links and adapted to effect primary angular displacement of the links by traversing the camming surfaces of the lifting hooks during the early portion of the downward excursion within the housing of the link suspending means, and further adapted to operatively align themselves with the reentrant surfaces of the lifting hooks upon the continued downward excursion of the link suspending means; link camming surfaces disposed one upon each of the links and adapted to effect secondary angular displacement of the links by traversing the camming surfaces of the lifting hooks during the latter portion of the downward excursion within the housing of the link suspending means; link stops disposed one upon one link of each pair of links; sears pivotally mounted one upon each of the link suspending 'means and adapted to coact each with the link stop complementary thereto to retain the links in the position assumed upon the secondary angular displacement thereof; and triggers mounted one upon each end of the housing, and adapted to coast each with the sear complementary thereto, when the link suspending means approach the upper limit of their excursion within the housing, to release the links from their last named position.

12. In a structure of the class described the combination, with a crane and a gate, of a pair of spaced apart lifting hooks affixed to the gate and provided each with a pair of oppositely disposed reentrant arcuate surfaces near the upper end and a pair of camming surfaces upon the upper face; a pair of link suspending means depended from the crane and adapted to motivation thereby; a housing disposed about the link suspendin means and relatively displaceable thereto vertically and adapted to position the link suspending meansv in registry with the lifting hooks; stop means disposed within the housing and adapted to limit the excursion therewithin of the link suspending means; coacting aligning means disposed on the gate and on the housing to operatively align the gate and the housing;

two pairs of links pivotally suspended one pair from each of the link suspending means; synchronizing means attached to both links of each pair and adapted to provide uniform angular displacement thereof; load bearing members affixed one to the lower end of each of the links and adapted to effect primary angular displacement of the links by traversing the camming surfaces of the lifting hooks during the early portion of the downward excursion within the housing of the link suspending means, and further adapted to operatively align themselves with the reentrant surfaces of the lifting hooks upon the continued downward excursion of the link suspending means; link camming surfaces disposed one upon each of the links and adapted to effect secondary angular displacement of the links by traversing the camming surfaces of the lifting hooks during the latter portion of the downward excursion within the housing of the link suspending means; link stops disposed one upon one link of each pair of links; sears pivotally mounted one upon each of the link suspending means and adapted to coact each with the link stop complementary thereto to retain the links in the position assumed upon the secondary angular displacement thereof; triggers mounted one upon each end of the housing, and adapted to coact each with the sear complementary thereto, when the link suspending means approach the upper limit of their excursion within the housing, to release the links from their last named position; and interlocking means interccnnecting the pairs of links.

13. A spillway gate comprising a gate lower section; a lower lifting hook attached to the gate lower section; a gate upper section adapted to be superimposed upon and aligned with the gate lower section; an upper lifting hook slidahly disposed within the gate upper section; a lower hook engaging means depending from the upper lifting hook and disposed within the gate upper section and displaceable relative thereto vertically within fixed limits, said lower hook engaging means being adapted automatically to engage the lower lifting hook after the gate upper section has been superimposed upon and aligned with the gate lower section and the lower hook engaging means has been lowered to hook engaging position; means within the gate upper section coacting with said automatic means arranged to automatically disengage the said automatic means from the lower hook by the act of lowering the said automatic means from the lower hook by the act of lowering the said automatic means within the spillway gate upper section to a point below the lower hook engaging position; and locking means within the gate upper section coacting with the upper lifting hook and the lower hook engaging means whereby the gate upper section and the gate lower section may be maintained in assembled relation when the lower lifting hook is engaged by the lower hook engaging means.

14. A spillway gate comprising a gate lower section; a plurality of lower lifting hooks attached to the gate lower section; a gate upper section adapted to be superimposed upon and aligned with the gate lower section; a plurality of upper lifting hooks slidably disposed within the gate upper section and in alignment with the lower lifting hooks; a plurality of lower hook engaging means depending one from each of the upper lifting hooks and disposed within the gate upper section and displaceable relative thereto vertically within fixed limits, said lower hook engaging means being each adapted automatically to engage the lower lifting hook in registry therewith after the gate upper section has been superimposed upon and aligned with the gate lower section and the lower hook engaging means has been lowered to hook engaging position; means within the gate upper section coacting with said aut0- matic means arranged to automatically disengage the said automatic means from the lower hooks by the act of lowering the said automatic [0 means within the spillway gate upper section to a point below the lower hook engaging position; locking means within the gate upper section coacting with the upper lifting hooks and the lower hook engaging means whereby the gate upper section and the gate lower section may be maintained in assembled relation when the lower lifting hooks are engaged. by the lower hook engaging means; and interlocking means interconnecting the lower hook engaging means.

NEIL B. MADSEN. 

